Basic Information

Section
612(c) of
the Clean Air Act (CAA) requires the Agency to publish
a list of acceptable and unacceptable substitutes for
ozone-depleting substances (ODS). The SNAP program
does not require that substitutes be risk- free to be
found acceptable. The Agency interprets Section 612 as
a mandate to identify substitutes that reduce risks
compared to use of class I or II compounds and other
substitutes for
class I or
class II
substances, rather than mandate to list as acceptable
only those substitutes that are risk free.

Acceptable alternatives are determined to reduce
overall risk to human health and the environment.
These alternatives may be used without restriction in
specific end-uses.

Acceptable subject to use conditions means that a
substitute is acceptable only if used in a certain
way. For example, substitutes for CFC-12 in
automotive air conditioning systems are acceptable
subject to a condition that the substitute be used
with unique equipment fittings such as for cars,
recovery and recycling, and refrigerant
containers.

Acceptable subject to narrowed use limits means
that a substitute may be used only within certain
specialized applications within a sector end-use, and
may not be used for other applications within an end
use or sector. For example, some alternative fire
suppressants may be used as total flooding agents in
normally unoccupied areas, but not in occupied
areas.

Unacceptable alternatives are prohibited because
the Administration has determined the use of the
substitutes pose significantly higher human health
and environmental risks than those risks from either
continued use of the class I substitutes themselves
or from use of other available substitutes. For
example, HCFC-141b must not be used for metals
cleaning, electronics cleaning, or precision cleaning
because of its high ozone depletion potential and the
refrigerant MT-31 must not be used in air
conditioning and other refrigerant uses because of
its toxicity.

Pending alternatives are those for which EPA
determines an extension of the 90 day review period
is necessary. A delay of the review period will not
affect a manufacturer’s ability to sell a
product 90 days after the agency issues a notice of
completion for a submission.

What is the difference between
a rule and a notice?

In general, substitutes found acceptable without
restriction will be published in a
notice of
acceptability. Substitutes that that are found
unacceptable or acceptable subject to restrictions will
go through a comment period and then be published as a
rule.

What Are the Guiding
Principles of the SNAP Program?

Evaluate substitutes within a comparative risk
framework- The program evaluates the risk of
alternative compounds compared to those of
ozone-depleting compounds and the available
alternatives. The environmental risk factors that are
considered include ozone depletion potential,
flammability, toxicity, occupational health and
safety, as well as contributions to global warming
and other environmental factors. There are also risk
factors associated with quality of information,
uncertainty of data, and economics factors including
feasibility and availability.

Do not require that substitutes be risk-free to be
found acceptable- The Agency finds substitutes to
be either acceptable, acceptable in restrictions, or
unacceptable by the Agency. For substitutes to be
found acceptable they must have a reduced risk, which
is not necessarily risk free, compared to ozone
depleting compounds in class I or class II.

Restrict only those substitutes that are
significantly worse- The EPA does not intend to
restrict a substitute if it has only marginally
greater risk than another substitute. Drawing fine
distinctions concerning the acceptability of
substitutes would be extremely difficult given the
variability in how each substitute can be used within
a specific application and the resulting
uncertainties surrounding potential health and
environmental effects. The Agency also does not want
to intercede in the market's choice of available
substitutes, unless a substitute has been proposed or
is being used that is clearly more harmful to human
health and the environment than other
alternatives.

Evaluate risks by use- Section 612 requires
that substitutes be evaluated by use. Environmental
and human health exposures can vary significantly
depending on the particular application of a
substitute. Thus, the risk characterizations must be
designed to represent differences in the
environmental and human health effects associated
with diverse uses. This approach cannot, however,
imply fundamental tradeoffs with respect to different
types of risk to either the environment or to human
health.

Provide the regulated community with information
as soon as possible- The Agency recognizes the
need to provide the regulated community with
information on the acceptability of various
substitutes as soon as possible. Future
determinations on the acceptability of new
substitutes are published several times a year.

Do not endorse products manufactured by specific
companies- The Agency does not issue
company-specific product endorsements. In many cases,
the Agency may base its analysis on data received on
individual products, but addition of a substitute to
the acceptable list based on that analysis does not
represent endorsement of that company's products.
Generally, placement on the list merely constitutes
an acknowledgement that a particular product made by
a company has been found to be acceptable under
SNAP.

Defer to other environmental regulations when
warranted- In some cases, EPA and other federal
agencies have developed extensive regulations under
other statutes or other parts of the CAA that address
any potential cross- or inter-media transfers that
result from the alternatives to class I and class II
substances. The SNAP program will take existing
regulations into account. For example, EPA considers
the additional safety added by existing environmental
regulations on hazardous air pollutants or hazardous
waste or by existing regulations for occupational
safety and health.

What Are EPA's Criteria for
Evaluating Alternatives?

EPA's evaluation of each substitute in an end-use is
based on the following types of information and
analyses.
40
CFR 82.178 details the specific data to be submitted:

Atmospheric effects-

The SNAP program considers the ozone depletion
potential and 100-year integrated global warming
potential of compounds to assess atmospheric
effects.

Exposure assessments-

Exposure assessments are used to estimate
concentration levels of substitutes to which
workers, consumers, the general population, and
environmental receptors may be exposed over a
determined period of time. These assessments are
based on personal monitoring data or area sampling
data if available. Exposure assessments may be
conducted for many types of releases including:

Releases in the workplace and in homes

Releases to ambient air and surface
water

Releases from the management of solid
wastes

Toxicity data-

Toxicity data is used to assess the possible
health and environmental effects for exposure to
substitutes. The Occupational Safety and Health
Administration (OSHA) or EPA approve wide health
based criteria that is available for a substitute
such as:

Permissible Exposure Limits (PELs for
occupational exposure)

Inhalation reference concentrations (RfCs for
noncarcinogenic effects on the general
population)

Cancer slope factors (for carcinogenic risk
to members of the general population)

If OSHA has not issued a PEL for a compound,
EPA also considers Workplace Environmental Exposure
Limits set by the American Industrial Hygiene
Association or Threshold Limit Values set by the
American Conference of Governmental Industrial
Hygienists. If limits for occupational exposure or
exposure to the general population are not already
established, then EPA derives these values
following the Agency's peer reviewed guidelines.

Exposure information is combined with is
combined with this toxicity information to explore
any basis for concern. Toxicity data is used with
existing EPA guidelines to develop health-based
criteria for interim use in these risk
characterizations.

Flammability-

Flammability is examined as a safety concern
for workers and consumers. EPA assesses
flammability risk using data on:

The SNAP program also examines other potential
environmental impacts such as ecotoxicity and local
air quality impacts. A compound that is likely to
be discharged to water may be evaluated for impacts
on aquatic life. Some substitutes are volatile
organic compounds (VOCs), which are chemicals that
increase tropospheric air pollution by contributing
to ground-level ozone formation. In addition, EPA
notes whenever a potential substitute is considered
a hazardous air pollutant or hazardous waste.